CASELLA USA WHAT IS …? GLOSSARY OF ACOUSTIC TOPICS What is…..? A brief guide to some of the more common terms and concepts used in industrial and environmental acoustics and the noise instruments used for measurements. CEL-240 CEL-320/360 CEL-350 CEL-430/450 CEL-600 The CEL family of Quality Noise meters From Casella USA These pages are intended to provide a simplified explanation to some of the more common (and not so common) terms that a new user of sound level meters or noise dosimeters might encounter when using CEL noise instruments for the first time. This text is not intended to be exhaustive. For strict definitions of the terms found in this document the user is directed to relevant ANSI, ASTM, ISO & IEC texts. Written by Bob Selwyn V.P Sales and Marketing, Casella USA Originally Started Saturday, November 03, 2001 Lastupdated Friday,February12,2010 Casella USA Page 1 of 34 (800) 366-2966 [email protected] last updated 02/12/2010 CASELLA USA WHAT IS …? GLOSSARY OF ACOUSTIC TOPICS Contents ‘A’ weighting.......................................................................................................................... 8 Absorption............................................................................................................................... 8 Absorption coefficient ............................................................................................................ 8 Accuracy ................................................................................................................................. 8 A.C.G.I.H................................................................................................................................ 8 Acoustics................................................................................................................................. 8 Acoustic trauma ...................................................................................................................... 8 Airborne sound........................................................................................................................ 8 Ambient noise ......................................................................................................................... 8 Amplitude ............................................................................................................................... 8 Analog display ........................................................................................................................ 9 Anechoic chamber .................................................................................................................. 9 A.N.S.I. ................................................................................................................................... 9 Articulation index (AI) ........................................................................................................... 9 ASHRAE................................................................................................................................. 9 A.S.T.M. ................................................................................................................................. 9 Attenuation.............................................................................................................................. 9 Audio frequency...................................................................................................................... 9 Audiogram .............................................................................................................................. 9 Audiometer ............................................................................................................................. 9 Average noise level (Lavg)..................................................................................................... 9 ‘B’ weighting ........................................................................................................................ 10 Back erase ............................................................................................................................. 10 Background noise level (dB) ................................................................................................ 10 Band ...................................................................................................................................... 10 Band pass filter ..................................................................................................................... 10 Barrier ................................................................................................................................... 10 Baseline audiogram............................................................................................................... 10 Broadband noise.................................................................................................................... 10 Broadband noise level (dB) .................................................................................................. 10 Building acoustics................................................................................................................. 10 ‘C’ weighting ........................................................................................................................ 10 Calibration............................................................................................................................. 10 Calibrator .............................................................................................................................. 11 Ceiling level.......................................................................................................................... 11 Chart recorder ....................................................................................................................... 11 Cochlea ................................................................................................................................. 11 Community noise equivalent level (CNEL) ......................................................................... 11 Constant bandwidth filter...................................................................................................... 11 Constant percentage bandwidth filter ................................................................................... 11 Crest factor (CF) ................................................................................................................... 11 Criterion level (dB)............................................................................................................... 11 Cumulative............................................................................................................................ 11 Casella USA Page 2 of 34 (800) 366-2966 [email protected] last updated 02/12/2010 CASELLA USA WHAT IS …? GLOSSARY OF ACOUSTIC TOPICS Cumulative distribution (%) ................................................................................................. 12 Cumulative distribution level (dB) ....................................................................................... 12 Cutoff frequency ................................................................................................................... 12 Cutoff level (dB)................................................................................................................... 12 Cycle ..................................................................................................................................... 12 Cycles per second (cps) ........................................................................................................ 12 Daily personal noise exposure level (LEP,d)........................................................................ 12 Damping................................................................................................................................ 12 Data logging.......................................................................................................................... 12 Day Night Noise Level (LDN) ............................................................................................. 13 Derate.................................................................................................................................... 13 Digital audio tape (DAT)...................................................................................................... 13 dB.......................................................................................................................................... 13 Decibel (dB).......................................................................................................................... 13 Digital signal processing (DSP)............................................................................................ 13 Diffraction............................................................................................................................. 13 Directivity ............................................................................................................................. 13 Directivity index (DI) ........................................................................................................... 13 D.o.D..................................................................................................................................... 13 Doppler effect